Bright Yellowish-Red Pigment Based on Hematite/Alumina Composites with a Unique Porous Disk-like Structure

Hideki Hashimoto, Jun Kiyohara, Arisa Isozaki, Yuya Arakawa, Tatsuo Fujii, Jun Takada, Hirofumi Inada, Taigo Takaishi, Hidetaka Asoh

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14 Citations (Scopus)


Inspired by a bacteriogenic, iron-based oxide material and a traditional Japanese red pigment, a bright yellowish-red pigment was prepared by heating an Al-containing iron oxyhydroxide precursor. The obtained red pigment had a unique porous disk-like structure, comprising Al-substituted hematite particles and crystalline alumina nanoparticles. Although these disk-like structures loosely gathered to form an aggregate in powder, they can be easily dispersed into a single, disk-like structure by simple ultrasonic irradiation. The powder exhibited a bright yellowish-red color and high thermostability, making it attractive as a coloring material for various industrial products needing a bright-red color, high weather resistance, and durability. Quantitative color measurements revealed extremely high L*, a*, and b∗ values that are much greater than those of commercially available hematite. The thermostability test showed that even after exposure to high temperatures, the pigment retained the red color, indicating its high thermostability. The unique microstructure should be strongly related to the bright yellowish-red color and the high thermostability of the developed red pigment.

Original languageEnglish
Pages (from-to)4330-4337
Number of pages8
JournalACS Omega
Issue number8
Publication statusPublished - Mar 3 2020

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)


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